#include "reg52.h"

sbit S7 = P3^0;
sbit S6 = P3^1;
sbit S5 = P3^2;
sbit S4 = P3^3;

sbit L1 = P0^0;
sbit L2 = P0^1;
sbit L3 = P0^2;
sbit L4 = P0^3;
sbit L5 = P0^4;
sbit L6 = P0^5;
sbit L7 = P0^6;
sbit L8 = P0^7;

void Slect573(unsigned char n)
{
	switch(n)
	{
		case 4:
			P2 = (P2 & 0x1f) | 0x80;
		break;
		case 5:
			P2 = (P2 & 0x1f) | 0xa0;
			break;
		case 6:
			P2 = (P2 & 0x1f) | 0xc0;
		break;		
		case 7:
			P2 = (P2 & 0x1f) | 0xe0;
		break;		
	}
}

void DelayK(unsigned char t)
{
		while(t--);
}
	
unsigned char statK = 0;

void ScanKey()
{

	if(S7 == 0)
	{
		DelayK(100);				
		if(statK == 0)
		{
			L1 = 0;
			statK = 1;
		}
		else if(statK == 1)
		{
			DelayK(100);
			L1 = 1;
			statK = 0;
		}	
		while(S7 == 0);
	}
	if(S6 == 0)
	{
		DelayK(100);				
		if(statK == 0)
		{
			L2 = 0;
			statK = 2;
		}
		else if(statK == 2)
		{
			DelayK(100);
			L2 = 1;
			statK = 0;
		}
		while(S6 == 0);
	}
	if(statK == 1)
	{
			DelayK(100);			
			if(S5 == 0)
			{
				L3 = 0;
				while(S5 == 0);
				L3 = 1;
			}
		
			if(S4 == 0)
			{
				L4 = 0;
				while(S4 == 0);
				L4 = 1;
			}
	}
	
	if(statK == 2)
	{
			DelayK(100);			
			if(S5 == 0)
			{
				L5 = 0;
				while(S5 == 0);
				L5 = 1;
			}
		
			if(S4 == 0)
			{
				L6 = 0;
				while(S4 == 0);
				L6 = 1;
			}
	}

}
	
void main()
{
	Slect573(4);
	while(1)
	{
	ScanKey();
	}
}










